Multiple and Concurrent Arrhythmia.

Given the unique interventional emphasis in our specialty, Teaching Rounds in Cardiac Electrophysiology has frequently centered on the pearls and pitfalls associated with electrogram analysis and complications of lead implant extraction or ablation and in mapping complex arrhythmia circuits. In this issue of Circulation: Arrhythmia and Electrophysiology, Fabrizio et al, in a refreshing departure from this norm, take us to a more classic medical teaching rounds relevant to rhythm management. They present a patient with multiple changing malignant rhythm disorders resulting from caffeine toxicity. Their submission is replete with clinical diagnostic dilemmas, treatment difficulties, and also a succinct but comprehensive discussion of caffeine toxicity and the heart.